code: def test_sma_std():
      orig = np.array(
          [
              [
                  np.nan,
                  0.7071067811865476,
                  0.7071067811865476,
                  0.7071067811865476,
                  0.7071067811865476,
                  0.7071067811865476,
                  0.7071067811865476,
                  0.7071067811865476,
                  0.7071067811865476,
                  0.7071067811865476,
              ],
              [
                  np.nan,
                  0.7071067811865476,
                  2.1213203435596424,
                  3.5355339059327378,
                  4.949747468305833,
                  6.363961030678928,
                  7.7781745930520225,
                  9.192388155425117,
                  10.606601717798213,
                  12.020815280171307,
              ],
          ]
      )
      dforig = pd.DataFrame({"0": orig[0], "1": orig[1]}).dropna()
      l1 = range(10)
      l2 = [i**2 for i in range(10)]
      df = pd.DataFrame({"0": l1, "1": l2}).astype(np.float64)
      res = sma_std(df, span=2).dropna()
      assert all((abs(dforig - res) <= 1e-15).all())
  
file_path: FinQuant/tests/test_moving_average.py
imports: import matplotlib.pyplot
  import numpy
  import pandas
  from finquant.moving_average import compute_ma, ema, ema_std, plot_bollinger_band, sma, sma_std
label_desc: Use image node_id 3 for calling a global function with example usage: test_sma_std() without return types